Conventionally, the Universal Shipborne Automatic Identification System (referred to as “AIS” below) is used for collision avoidance and personal safety (see Patent Document 1 listed below).
AIS data includes, as static information, for example the vessel's Maritime Mobile Service Identity (MMSI), radio call sign and ship name, IMO number, ship length and width, ship type, and positions of the positioning system antennas, and as dynamic information, for example longitude and altitude, coordinated universal time, location accuracy, ground course, ground speed, heading, angular turning speed, and navigation status. As navigation-related information, the AIS data furthermore includes for example the vessel's draught, types of hazardous objects/substances on board, destination, and arrival time at destination, and it includes also navigational safety-related information. This AIS data is exchanged, as a vessel identification signal, by radio communication within a predetermined transmission distance. DSC has been in existence since before AIS, and includes a ringer for calling other ships, emergency navigation status, such as DISTRESS, and new instructions for transmit/receive signals by the base station.
An apparatus for transmitting/receiving AIS data includes by standard a display, namely a minimum keyboard display (MKD). Ordinarily the amount of displayed information displayed by this display is very sparse, in order to comply with the specifications for an extreme environment and to achieve a minimum display performance.
According to Patent Document 1, a conventional apparatus for displaying the various kinds of vessel information included in the AIS data employs the method of displaying on a screen of a radar apparatus information concerning each vessel according to the AIS data.
This apparatus compares the position information of other ships according to the AIS data with position information of other ships obtained by radar, displays the positions of specific ships for which there is a match with registered content on a nautical chart, and displays the detailed information concerning these specific ships in an independent display area separate from the nautical chart.    Patent Document 1: JP2001-281331A